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铁作为地壳中丰度最高的氧化还原敏感元素,对湖泊沉积物的氧化还原作用具有重要的指示意义.水生植物根系泌氧在根际形成微域的氧化圈,根际是氧化、还原同时发生的生物活跃区.以轮叶黑藻(Hydrilla verticillata)为研究对象,利用微电极和荧光定量PCR探讨根系泌氧作用对沉积物中典型铁氧化菌(嘉利翁氏菌)和典型铁还原菌(地杆菌)的影响.结果表明,轮叶黑藻生长迅速,通过根系泌氧作用影响沉积物中铁的价态和形态,是根际铁循环的重要参数,并对根际微区微生物有一定的影响.根系泌氧使根际嘉利翁氏菌和地杆菌数量增加,进一步影响根际微生物铁循环.实验结果可为微生物对根际铁循环的研究提供一定的理论基础. 相似文献
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Physicochemical and microbiological characterization of anoxic sediments taken from seven highly polluted sites of the Marmara Sea was carried out. The 16S rRNA based microbial community structure analyses were performed using domain-specific PCR followed by denaturant gradient gel electrophoresis (DGGE) and sequencing of characteristic bands. The results showed that the microbial communities in these sediments were diverse and evenly distributed. Relating the prokaryotic and geochemical variables through statistical tools revealed that the microbial diversity in the sediments significantly related to depth, and S, Mn and Fe content of the sediments. Fermentative bacteria, denitrifying bacteria and hydrogenotrophic methanogens were dominant whereas sulfate reducing bacteria were absent in the DGGE patterns. This unusual microbial community structure implied that the newly discovered anaerobic methane oxidation coupled to denitrification process may occur in these subseafloor environments. 相似文献
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Geochemical processes involving redox reactions and leading to either formation or transformation of geochemical barriers may be largely induced or enhanced by microbial activity. The microbial reduction of uranium is studied as a strategy for rehabilitation of uranium-containing groundwater. The bioremediation mechanism converts dissolved uranium(VI) into low-solubility U(IV). The processes involving dissimilatory reducing bacteria, which facilitate the reduction and retention of U(VI) in soils and rocks, are considered. The diversity of microorganisms involved in anaerobic reduction of uranium is shown. The geochemical conditions that may affect the rate of microbial reduction of U(VI) are specified, i.e., the presence of nitrate ions, phosphate ions, calcium ions, and iron oxides. The mechanisms of their action are examined. Geochemical barriers with the participation of microorganisms are proposed for the rehabilitation of groundwater with uranium removed from groundwater and deposited locally as a result of microbial reduction of U(VI). 相似文献
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Snezana Maletic Jelena Beljin Dragana Tamindzija Marko Grgic Jelena Molnar Jazic Marijana Kragulj Isakovski Srdan Roncevic 《国际泥沙研究》2021,36(4):479-488
The purpose of the current study is to compare the influence of different aerobic conditions(biostimulation(BS),bioaugmentation(BA),and a combination of biostimulation and bioaugmentation(BB))on polycyclic aromatic hydrocarbons(PAH)degradation and compare the degraded amount with single step XAD-4 extraction as a new tool for bioavailability assessment for chronically contaminated sediment samples obtained from territory of Autonomous Province Vojvodina of Serbia(S1,S2,and S3).A great number of papers dealing with biodegradation of PAHs in spiked sediment or soil have been published,but to the authors’knowledge,a limited number of papers studied aged,historically polluted sediment and a sum of chosen U.S.Environmental Protection Agency(USEPA)PAHs.A significant reduction(up to67%)in PAH concentration was observed,while the percentage of reduction varied depending on the sediment sample and treatment used.BS treatment successfully stimulated growth of indigenous bacteria.Further,PAH-degrading strain Sphingomonas paucimobilis F8 inoculated in BA and BB treatment survived for up to 7 weeks after it was suppressed by unfavorable conditions or native microbes.Degraded amounts generally showed good correlation with results obtained from XAD-4 extraction.Results obtained in the current study represent a good start for standardizing a XAD-4 extraction technique as a simplified,easier,and lower cost method for bioavailability assessment. 相似文献
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Impact of anthropogenic activities on the sediment microbial communities of Baiyangdian shallow lake 总被引：1，自引：0，他引：1
《国际泥沙研究》2020,35(2):180-192
Microorganisms are recognized as sensors of external disturbance in freshwater ecosystems.In this study,sediment samples from regions with strong human activity interference(four sites),moderate human activity interference(five sites) and minor human activity interference(five sites) in Baiyangdian Lake were collected;and their physiological and chemical properties and heavy metals contents were analyzed.The structures of bacterial and fungal communities were tested using 16 S ribosomal Ribonucleic Acid(rRNA) and Internal Transcribed Spacer 2(ITS2) high-throughput sequencing technologies.The results indicated that Proteobacteria was the most abundant bacterial phylum.Ascomycota,Basidiomycota and Ciliophora were the dominant phyla of fungi.Obvious differences of microbial genera among the three regions we re obse rved,especially fungal genera.With intensified disturbance by human activities,the Simpson and Shannon indices of bacteria significantly decreased.The fungal communities were clustered into three groups in accordance with the different human disturbance levels.The bacterial communities of sediment samples under moderate and minor human disturbance appeared similar,but different from those under strong human disturbance.Redundancy analysis indicated that zinc,total phosphorus,copper,and lead were the dominant factors that influenced the bacterial community.Nitrifiers and sulfate-reducing bacteria were influenced by pH,nitrate(NO3),and total nitrogen.The fungal community was significantly affected by total phosphorus.This study reveals that sediment microbial community structures among different regions of a shallow lake are mainly impacted by human activities. 相似文献
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Response of the bacterial community to in situ bioremediation of organic-rich sediments 总被引：8，自引：0，他引：8
A field trial experiment was carried out to assess the potential of bioremediation for mobilisation of carbon in organic-rich sediments. Both bioaugmentation (bio-fixed microorganisms) and biostimulation (oxygen release compounds--ORC) protocols have been tested and the response of the bacterial community has been described to assess the baseline for bioremediation potential. Multifactorial ANOVA revealed that bioaugmentation protocol had an effect in stimulate mobilisation processes and significantly enhanced extra-cellular enzymatic activity rates. In contrast biostimulation treatment did not have an effect on mobilisation rates but contributed to enhance bacterial efficiency through a maximization of the bacterial production:enzymatic activity ratio. Average calculation of net mobilised carbon showed that 23% increase of mobilised pool was accounted for bioaugmentation in summer. Although biostimulation accounted for a smaller increase in mobilised carbon (<10%), the use of ORC resulted in an increased mineralisation and net carbon loss via respiration. Based on our results, a conceptual model for application of bioremediation to face the problem of sediment eutrophication is discussed. 相似文献
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Bioremediation of petroleum hydrocarbons in anoxic marine sediments: Consequences on the speciation of heavy metals 总被引：3，自引：0，他引：3
Antonio Dell’Anno Francesca Beolchini Massimo Gabellini Laura Rocchetti Antonio Pusceddu Roberto Danovaro 《Marine pollution bulletin》2009,58(12):1808-1814
We investigated the effects of biostimulation and bioagumentation strategies applied to harbor sediments displaying reducing conditions and high concentrations of petroleum hydrocarbons and heavy metals. We compared the microbial efficiency of hydrocarbon removal from sediments maintained for 60 days in anoxic conditions and inoculated with acetate, sulfate-reducing bacterial strains and acetate and sulfate-reducing bacteria. All treatments determined a significant increase in the microbial growth and significant decreases of hydrocarbon contents and of redox potential values. The addition of sulfate-reducing bacterial strains to the sediment was the most efficient treatment for the hydrocarbon removal. In all experiments, significant changes of the heavy metals’ phase repartition were observed. The results reported here suggest that the biodegradation of petroleum hydrocarbons in anoxic marine sediments may be enhanced by stimulating microbial anaerobic metabolism, but care should be applied to monitor the potential changes in the mobility and bioavailability of heavy metals induced by bio-treatments. 相似文献
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Carmen Lourdes Yupanqui Zaa Joan E. McLean R. Ryan Dupont Jeanette M. Norton Darwin L. Sorensen 《Ground Water Monitoring & Remediation》2010,30(1):46-57
Dehalorespiration bioremediation has been considered for chlorinated compound removal from two trichloroethene contaminated groundwater plumes in the OU 5 area of Hill Air Force Base, Utah. The distributions and population densities of the 16S rRNA genes of Bacteria, Dehalococcoides ethenogenes, Desulfuromonas michiganensis, Geobacter spp. and Rhodoferax ferrireducens -like bacteria, as well as the functional genes trichloroethene reductive dehalogenase ( tce A) and vinyl chloride reductase ( vcr A) were determined in contaminated aquifer material samples. The influence of aquifer physical and chemical properties, including iron availability, on these distributions was evaluated. Twenty aquifer cores were collected. DNA was extracted and analyzed using real-time quantitative polymerase chain reaction (RT-qPCR) to quantify the gene densities. Dehalococcoides population densities were low and unevenly distributed. D. michiganensis was found in 12 cores while Geobacter spp. were found in 8 cores. Rhodoferax ferrireducens -like bacteria were widely distributed. The vcr A gene distribution was relatively uniform and broad but the tce A gene was detectable in only 2 cores. Gene distribution was not related to core clusters derived from physical/chemical characteristics. 相似文献
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底泥细菌代谢是城市河道底泥代谢物的主要来源,最终决定城市河道的生态状况.本文研究了黑臭河道底泥经添加硝酸钙、生物促生剂和种植沉水植物处理后底泥中细菌群落结构的响应,以期为城市黑臭河道细菌群落的改善和综合治理提供理论依据.实验结果表明:经过不同生态处理后,上覆水中,添加硝酸钙组总氮(TN)含量显著高于对照组,添加生物促生剂组溶解氧浓度显著高于对照组.沉积物中,所有处理组的氧化还原电位值(ORP)均显著高于对照组,种植沉水植物组和添加硝酸钙组TN含量均显著低于对照组,沉积物理化性质得到一定改善.对不同生态处理组底泥细菌群落的研究发现,处理组底泥细菌群落产生了较大变化,且不同处理组细菌群落变化不同,生物促生剂组底泥中细菌的Sobs指数和Chao 1指数显著高于对照组和硝酸钙组,且生物促生剂组Shannon指数和PD指数显著高于硝酸钙组.Proteobacteria(Deltaproteobacteria、Betaproteobacteria、Gammaproteobacteria)、Chloroflexi、Firmicutes、Bacteroidetes和Spirochaetae是各实验组的主要优势菌门;非度量多维尺度分析表明:硝酸钙和生物促生剂的投加可明显改变底泥细菌群落结构组成.在属水平上,uncultured_Anaerolineaceae、Ferribacterium、uncultured_Xanthomonadales_Incertae_Sedis是导致底泥细菌群落发生变化的主要菌属.冗余分析结果表明,底泥ORP的变化是驱动细菌群落结构变化的关键环境因素. 相似文献
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An experiment was conducted to determine if biodegradation of trichloroethylene (TCE) can occur in previously uncontaminated ground water in saturated fractured saprolite (highly weathered material derived from sedimentary rocks). Two undisturbed columns (0.23 m diameter by 0.25 m long) of fractured saprolite were collected from approximately 2 m depth at an uncontaminated site on the Oak Ridge Reservation, Oak Ridge, Tennessee. Natural, uncontaminated ground water from the site, which was degassed and spiked with dissolved phase TCE, was continuously pumped through one column containing the natural microbial communities (the biotic column). In a second column, the microorganisms were inhibited and the dissolved phase TCE was added under aerobic conditions (dissolved oxygen conditions > 2 ppm). In effluent from the biotic column, reducing conditions rapidly developed and evidence of anaerobic biodegradation of TCE, by the production of cDCE, first appeared approximately 31 days after addition of TCE. Reductive dechlorination of TCE occurred after iron-reducing conditions were established and about the same time that sulfate reduction began. There was no evidence of methanogenesis. Analyses using polymerase chain reaction with specific primers sets detected the bacteria Geothrix, Geobacter, and Desulfococcus-Desulfonema-Desulfosarcina in the effluent of the biotic column, but no methanogens. The presence of these bacteria is consistent with iron- and sulfate-reducing conditions. In the inhibited column, there were no indicators of TCE degradation. Natural organic matter that occurs in the saprolite and ground water at the site is the most likely primary electron donor for supporting reductive dechlorination of TCE. The relatively rapid appearance of indicators of TCE dechlorination suggests that these processes may occur even in settings where low oxygen conditions occur seasonally due to changes in the water table. 相似文献
11.
Dahllöf I Agrenius S Blanck H Hall P Magnusson K Molander S 《Marine pollution bulletin》2001,42(8):689-695
The effect of tri-n-butyl tin (TBT) on an intact marine sediment community after five months exposure was investigated. Changes in the structure of macro- and meiofauna communities were determined, as well as the functional diversity of the microbial community using BIOLOG microplates for Gram negative bacteria. Development of tolerance in the microbial community was investigated using Pollution Induced Community Tolerance (PICT) experiments with fluxes of nutrients as effect indicators. TBT affected the structure and recruitment of the macro- and meiofauna at nominal additions of 30-137 micromol TBT/m2 sediment. Number of species, diversity, biomass and community similarity was reduced at these concentrations compared to control. Species that molt seemed to be the most tolerant since they were predominant in boxes that had received the highest TBT addition and echinoderms were the most sensitive species. Renewed addition of TBT in PICT experiments with sediment from each boxcosm showed that TBT had an effect on individual nutrient fluxes from all sediments. Analyses of the flux patterns revealed a memory of previous TBT exposure, either due to induced tolerance or other community conditioning. 相似文献
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Xia Zhang Qianru Chen Chuan Wang Hongpei Zhang Yuqing Zhao Liping Zhang Biyun Liu Zhenbin Wu Qiaohong Zhou 《国际泥沙研究》2021,36(2):221-228
The process of urbanization aggravates the endogenous pollution of urban lake sediment,and polluted sediment may seriously affect the quality of the water in lakes.At present,it is difficult to distinguish the difference between sediment that is heavily polluted by nitrogen(N)and phosphorus(P)when using an analysis based on a physicochemical index classification.The current study applied phospholipid fatty acid(PLFA)technology to further analyze the sediment characteristics from the perspective of microbiology.Surface sediment from five urban lakes that are heavily polluted with N and P in Wuhan were sampled.Statistical approaches were used to analyze the microbial community structure in the sampled sediment,and to determine the correlations between the microorganisms and physicochemical indices.The most severely polluted lake sediment had similar PLFA structures,the highest saturated fatty-acid content,and bacteria as the dominant microorganism.However,there were differences between the microbial biomass of the various sediment samples,which may have been related to the degree of N and P pollution.Analysis of the microbial diversity in the sediment samples indicated that the bacteria were experiencing starvation and nutrient pressure,which may have been due to the dissolved oxygen concentration of the heavily polluted lake sediment.A correlation analysis showed that the endogenous N and P had different effects on the microbes of the polluted sediment.A redundancy analysis(RDA)demonstrated that the N/P ratio had the greatest influence on the PLFA species,accounting for 83%of the cumulative interpretation.To effectively promote the role of sediment microorganisms on circulating elements,it is necessary to regulate the N/P ratio of the sediment to some extent.When the N/P ratio in sediment exceeds 6,N pollution should be prioritized. 相似文献
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模拟湖泊系统构建了"沉积物-水-苦草(Vallisneria natans)"系统,应用磷脂脂肪酸(PLFAs)法测定在沉水植物苦草不同生长时期沉积物表层微生物群落结构的变化,探讨沉水植物对沉积物中的微生物群落结构的影响.结果表明,从苦草生长初期到旺盛期再到衰亡期,沉积物中有机质含量先下降后上升;总磷、有机磷、无机磷分别下降了8.97%、7.81%、10.28%;沉积物微生物的活性与总磷呈极显著负相关,在苦草生长初期和旺盛期,实验组的沉积物微生物活性大于对照组,而在衰亡期对照组的沉积物微生物活性略高于实验组;不同时期沉积物中微生物群落结构发生了明显变化,组成结构差异显著,微生物组成中细菌占主要成分(占微生物总量的76%~84%);细菌中革兰氏阳性菌占主要优势,且革兰氏阳性菌百分含量随苦草生长呈上升趋势,革兰氏阴性菌呈下降趋势;真菌的百分含量呈上升趋势. 相似文献
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Kalundborg Fjord is a Danish marine area which has been heavily oil polluted by refinery effluent, leading to accumulation of petroleum hydrocarbons in the surface sediments. A study of the occurrence in the sediment of heterotrophic bacteria, yeasts and filamentous fungi has been carried out, and the physiological composition of the microbial community has been recorded. Though the abundance of oil-degrading microorganisms was significant, a correlation between the number of these and the oil content of the sediment could not be demonstrated. 相似文献
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《国际泥沙研究》2020,35(3):227-236
The spatial distribution of bacterial communities inhabiting sediment is heterogeneous at different spatial scales,but mostly unexplored.Here,it is postulated that the heterogeneity of the bacterial community composition varies at the same scale of the heterogeneity of sediment chemical properties.The large spatial scale(km) diversity in sediment from a brackish water lagoon(Chilika Lake,India) is studied,considering the large scale physical and chemical characteristics of land cover,climate,pH,and salinity.Seventy-two samples(24 stations,3 seasons:winter,rainy,and summer) of sediment from Chilika Lake were analyzed by 16 S ribosomal ribonucleic acid(rRNA) gene sequencing,and the relations with land cover and other physico-chemical paramete rs are discussed.Mo re samples were collected after a severe cyclonic storm(Phailin) passed near the lagoon in 2013,to see the impact of the tropical storm on the spatial and tempo ral distribution of bacteria in the sediment.The results demonstrate clear spatial relations between physico-chemical parameters(e.g.,salinity),land surfaces(e.g.,drainage area),and the distribution of sediment microbial communities. 相似文献
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Influence of Carbon and Microbial Community Priming on the Attenuation of Uranium in a Contaminated Floodplain Aquifer 
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下载免费PDF全文 P.J. Mouser L.A. N'Guessan N.P. Qafoku M. Sinha K.H. Williams M. Dangelmayr C.T. Resch A. Peacock Z. Wang L. Figueroa P.E. Long 《Ground water》2015,53(4):600-613
The capacity for subsurface sediments to sequester radionuclide contaminants, such as uranium (U), and retain them after bioremediation efforts are completed is critical to the long‐term stewardship of re‐mediated sites. In U bioremediation strategies, carbon amendment stimulates bioreduction of U(VI) to U(IV), immobilizing it within the sediments. Sediments enriched in natural organic matter are naturally capable of sequestering significant U, but may serve as sources to the aquifer, contributing to plume persistence. Two types of organic‐rich sediments were compared to better understand U release mechanisms. Sediments that were artificially primed for U removal were retrieved from an area previously biostimulated while detrital‐rich sediments were collected from a location never subject to amendment. Batch incubations demonstrated that primed sediments rapidly removed uranium from the groundwater, whereas naturally reduced sediments released a sizeable portion of U before U(VI)‐reduction commenced. Column experiments confirmed that U release persisted for 65 pore volumes in naturally reduced sediments, demonstrating their sink‐source behavior. Acetate addition to primed sediments shifted the microbial community from sulfate‐reducing bacteria within Desulfobacteraceae to the iron‐reducing Geobacteraceae and Firmicutes, associated with efficient U(VI) removal and retention, respectively. In contrast, Geobacteraceae communities in naturally reduced sediments were replaced by sequences with similarity to Pseudomonas spp. during U release, while U(VI) removal only occurred with enrichment of Firmicutes. These investigations stress the importance of characterizing zones with heterogeneous carbon pools at U‐contaminated sites prior to the determination of a remedial strategy to identify areas, which may contribute to long‐term sourcing of the contaminants. 相似文献
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湖泊底泥疏浚环境效应:Ⅳ.对沉积物微生物活性与群落功能多样性的影响及其意义 总被引：5，自引：1，他引：4
通过为期一年的疏浚模拟试验,在试验室培养疏浚与对照柱样研究了底泥疏浚对沉积物微生物活性和群落功能多样性的影响。研究结果表明,太湖梅梁湾研究区模拟疏浚表层30cm对沉积物物理、化学和微生物性质影响较大。疏浚沉积物微生物活性显著低于未疏浚沉积物的微生物活性,疏浚对沉积物微生物活性影响较大且在一年的试验周期内难以恢复。底泥疏浚对沉积物微生物功能多样性产生影响,疏浚后初期新生表层沉积物的微生物群落多样性指数显著低于未疏浚沉积物,底泥疏浚改变了沉积物中微生物群落组成,并会导致微生物群落功能多样性降低。底泥疏浚对微生物活性与微生物群落功能多样性产生影响,从而对沉积物中生源要素的循环产生影响。 相似文献
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